1. Technical Field of the Invention
The present invention relates to a vibration motor which is used in a portable electronic equipment such as a portable telephone, a pocket bell or the like, and which silently informs a user of incoming etc. by vibration, and relates to a portable electronic equipment having the vibration motor.
2. Description of the Related Art
JP-A-10-248203 discloses one of conventional vibration motors used as silent information sources in miniature radio communication equipment, in which a cored-type brushless vibration motor is disclosed.
FIG. 6 is a sectional view of a main portion of the cored-type brushless vibration motor.
In FIG. 6, a bearing holder portion 102 is provided at the center of a bracket 101 forming the bottom of the vibration motor. This bearing holder portion 102 has a catch portion 103 and an erected portion 104 formed by cutting and erecting a part of the bracket 101.
A sintered oilloss bearing 105 is attached to the inside of this bearing holder portion 102 through a cover plate 106, and a stator core 109 having an armature coil 110 wound on a plurality of salient poles 107 is attached to the outside.
A rotor 110 has a magnet holder 111 and a cylindrical magnet 113 fixed to the magnet holder 111 and having a plurality of field poles disposed in a blade portion 112 of the stator core 109 through a radial gap. Further, the rotating body 110 is fitted by pressing a shaft 115 into a burring hole 114 disposed at the rotation center of the magnet 113. In addition, one end of the shaft 115 is rotatably supported by the sintered oilloss bearing 105, and the other end is rotatably supported through a similar sintered oilless bearing by a case 116 having another function as a cover.
In addition, a power supply method is to connect a terminal of the coil to one side of a flexible printed board so as to drive the motor.
However, in the above-mentioned conventional art, a usual vibration motor is extracted by an automatic sucking machine, automatically arranged on a board and subjected to assembling in a normal automatic assembling/wiring process in the case where the vibration motor is supplied by a parts maker in the packaged form of a pallet, a reel or the like. In that case, first, the vibration motor cannot be extracted by the automatic sucking machine if the vibration motor has a shape similar to that as mentioned above. That is, the automatic sucking machine sucks the ceiling of a part pneumatically. However, the aforementioned vibration motor is not even in the ceiling of the vibration motor because a sintered oilless bearing for rotatably supporting a shaft lies at the center of a cover. Therefore, even if the ceiling is sucked pneumatically by the automatic sucking machine, the air leaks from a gap between the shaft and the bearing so that sucking of the ceiling cannot be performed.
Further, since the vibration motor in the conventional art is not designed to suit a reflow soldering, special parts are required for assembling the vibration motor into a miniature radio communication equipment and holding the vibration motor therein, and the work for making the above operation demands expert employees, so that the number of labor-hour and the cost are increased. It is therefore necessary to make the vibration motor at least suitable for the reflow soldering so that the vibration motor can be applied to an automatic assembling process for mass production.
In the reflow soldering method, after parts to be mounted are arranged on a printed board, the parts and the board are passed through a reflow furnace so as to be connected with each other by solder. This solder is obtained in a way such that creamy solder is passed through an atmosphere at a high temperature to be fused and then the fused solder is solidified after being cooled. Here, it is necessary to pay attention to the case where solder balls scattering in the reflow furnace adhere to a coil or a magnet in the middle of the reflow soldering. In that case, it is necessary to give enough consideration to such a trouble that such an adhering solder ball blocks starting when the vibration motor starts, or such a solder ball rubs on the coil, the magnet or the like so as to generate irregular noise, etc.
In addition, even if the vibration motor is mounted on the printed board, it is necessary to perform accurate or proper positioning of the vibration motor. It is therefore necessary to take a dimensional measurement of the mounted position of the vibration motor. There are a large number of problems like the above matters when the reflow soldering is performed.
That is, in order to perform the reflow soldering perfectly so as to automate a wiring/assembling process, there has been a problem that automation must be fulfilled in all the steps of the following items 1 to 4 while the quality have to be also guaranteed.
1. To extract supplied parts by means of an automatic sucking machine or the like.
2. To arrange the extracted parts onto a printed board automatically.
3. To take measures against solder balls in a reflow furnace.
4. To inspect the positions of the parts after the parts are mounted.